Abstract: A control circuit for turning off or on direct current flowing through an inductive load (12) to ground uses a semiconductor switch (11), for example a MOSFET, having a first input terminal (D), a control terminal (G), and a second output terminal (S) to the load. A semiconductor freewheel diode (16) is coupled between the switch second terminal and ground, in parallel with the load. The freewheel diode has a current-conducting state and a current non-conducting state. A switching-off current source (19) is coupled between the second terminal and the control terminal; it reduces the magnitude of the switching control current (.+-.I.sub.GS) flowing into the control terminal of the MOSFET, as a function of voltage at the second terminal of the switch and the input to the freewheel diode. A minimum value (.+-.II.sub.GSmin) of the switching control current is reached when the voltage at the second terminal of the switch reaches ground potential.

Abstract: An apparatus for driving an electromagnetic load by applying a high voltage at the initial driving stage and thereafter applying a constant hold current is provided with a switch for supplying high-voltage energy to the electromagnetic load from a capacitor for storing high-voltage energy and a control circuit responsive to an electric signal for starting electromagnetic load driving and the output voltage of the capacitor. The control circuit turns the switch on at application of the electric signal and keeps it on until the output voltage reaches a prescribed level. The apparatus of this configuration enables optimum timing of changeover from high-voltage application mode operation to hold mold operation with simple circuitry.

Abstract: An inductive load driver circuit with shared flyback protection includes a first transistor (209) which drives a first load (229), and a second transistor (231) drives a second load (251). A first clamp voltage steering diode (217) is coupled between an input terminal (207) of the first transistor (209) and a zener diode (203), and a second clamp voltage steering diode (239) coupled between an input terminal (233) of the second transistor (231) and the zener diode (203). A power supply terminal (201) is coupled to the zener diode (203).

Abstract: The control system for a linear solenoid valve controls output of an oil pressure according to a current value to be fed to the linear solenoid which operates the linear solenoid valve. A solenoid current monitor detects the current value fed to the linear solenoid and an IG voltage monitor detects the voltage level of the battery. A linear solenoid current value setting unit sets a target current value according to a target oil pressure level and a duty ratio setting unit sets a duty ratio for applying the battery voltage to the linear solenoid on the basis of signals coming from the current monitor, the voltage monitor and the current value setting unit. A solenoid driver applies the battery voltage to the linear solenoid for a predetermined period in accordance with the duty ratio set by the duty ratio setting unit.

Abstract: A solenoid driver (10) capable of detecting the operational status of a solenoid (12) including the position of an armature within a solenoid coil and an operational method. The solenoid driver (10) generates a first solenoid current within the solenoid (12) and measures a first decay time t.sub.1. The first solenoid current is insufficient to pull the armature into the coil of the solenoid (12). A comparator circuit (22) continuously monitors the solenoid current and initiates a timer within a counter circuit (34) to compute the first current decay time. A second solenoid current is generated within the solenoid (12) that is sufficient to pull the armature into the coil of the solenoid (12). The second solenoid current is turned off and a second decay time t.sub.2 is measured. The decay times are stored in storage registers (R1, R2) within a controller (36). The controller (36) compares the measured decay times with stored values and outputs the armature position information over a communications bus (34).

Abstract: An electronic circuit, and corresponding method, for controlling the closing velocity of electrical switchgear, includes an actuator and a current detection circuit that detects whether an optimum amount of current is flowing through the actuator. When the optimum amount of current is detected, a current optimizing resistor is inserted into the path of the current flowing through the actuator, thus limiting the current flowing through the actuator to the optimum amount. This, in turn, limits the closing velocity of the electrical switchgear and minimizes contact bounce.

Abstract: A circuit arrangement for monitoring a control circuit, which has a driver transistor with an inductive load and a second transistor in a circuit branch parallel to the inductive load, includes an additional, external current measuring device. A switching element, in particular a transistor and an ohmic measuring resistor, is provided parallel to the driver transistor. At a test instant, the current flowing through the inductive load is diverted to the measuring device and induces a voltage at the measuring resistor which is indicative of the status of the control circuit.

Abstract: The present invention disclosed and claimed herein comprises a backup power system to supply current to an electromechanical actuator (50) to position a mechanical device (52) to a fail-safe position upon failure of a primary electric power source (12). A capacitor (40) is provided for storing energy. The capacitor (40) is charged by the primary electric power source (12). A relay device (35) is also provided for disconnecting the primary control signal upon failure of the primary electric power source (12) and connecting the capacitor (40) to the electromechanical actuator (50) to supply electric current to the electromechanical actuator (50) to position the mechanical device (52) to a fail-safe position. The relay device (35) comprises a transistor (32) which is kept turned off by the primary electric power source (12) and upon failure of the primary electric power source (12), turns on and energizes an electric relay coil (34).

Abstract: Apparatus for mitigating the adverse effects of magnetic interference on the operation of a CRT is provided. More specifically, magnetic sensors are placed in a gap formed between a front bezel and a rear enclosure comprising a magnetic shield enclosing all but the viewing surface of a CRT. The gap serves to concentrate the on-axis magnetic field and the resultant signal from the sensors is amplified to drive current through a compensation coil located inside the front bezel and in front of the viewing surface of the CRT. The current generates a compensation field that mitigates the incoming on-axis magnetic field. The ambient magnetic field is also sensed by a three axis magnetic sensing assemblage located outside the magnetic shield. The output of the sensing arrangement is operated on to produce a trigger to start a degauss cycle.

Abstract: A proportional valve has an output proportional to an electrical input signal. In a preferred embodiment, the valve is actuated by a proportional solenoid having a coil which is controlled by a control signal in proportion to voltage or current. The proportional solenoid is controlled by a relatively high current such as a rectified mains voltage. A control circuit ensures that the coil of the proportional solenoid is not overloaded. Particularly, it ensures that a maximum current value is not exceeded. In this way, the mains supply required in prior art devices may be eliminated.

Abstract: A method for triggering an electromagnetic consumer with low coil resistance (solenoid for a Diesel injection pump) having a free-running circuit that can be switched over, and an apparatus for performing the method, regulate a voltage at an end stage to a predetermined value. This is accomplished by controlling the control voltage of the end stage during a turn-on phase until a turn-on peak current is reached and then regulating the holding current by repeatedly lowering the current through the end stage and keeping it constant to a predetermined value during a predetermined time period and then raising it again to a maximum value of the holding current until the consumer is turned off.

Abstract: The present invention is directed to a device intended to turn on loads and keep them on for a pre-established period of time and includes a remanence relay which includes a coil L, a movable contact 1, a fixed, normally opened contact 2b and a fixed, normally closed contact 2a. When a remote push switch S is pushed to its ON position, a first current flows through the coil L in a first direction to cause the movable contact 1 to move from engagement with the contact 2b to engagement with the contact 2a. As a result, power is applied to a load 5. When the switch S is opened, a timing circuit, which includes a capacitor C1, a resistor R3, an electric disruptive device D5 and a diode D4, is initiated which charges the capacitor C1. When the voltage of the capacitor C1 reaches the threshold voltage of the disruptive device D5, a second current opposite in direction to the first current flows through the coil L to cause the movable contact to move to the contact 2b and disconnect the load 5.

Abstract: The multi-channel ignition coil driver module of the present invention includes a control integrated circuit and multiple high current load driver integrated circuits housed within a common package. The control integrated circuit is formed of a semiconductor material manufactured in accordance with a standard low-voltage integrated circuit processing technology and is responsive to multiple control signal inputs to provide a corresponding multiple number of low voltage drive signals. Each of the high current load driver integrated circuits are formed of a semiconductor material manufactured in accordance with a high-voltage integrated circuit processing technology and are each responsive to a different one of the low voltage drive signals to energize a different one of a multiple number of high current loads. A current limit function is further provided in each of the multiple channels for limiting the corresponding load current to a predetermined level.

Abstract: The first zero crossing of the power signal, after the detection of an opening/closing signal, initiates a series of predetermined, timed, steps which reduces or eliminates the overvoltage after opening/closing a circuit breaker on a high power line.

Abstract: An apparatus for making permanent magnet material magnetizes a body of material including a primary winding which has portions wound on a first core carrying current in a first direction creating a first field of flux and a secondary winding having portions wound on a second core wherein the secondary winding carries current in a second opposing direction to create a second field of flux. Since the currents are flowing in opposing directions, the secondary field of flux is directed to oppose the first field of flux. The result of this is that the magnetizer is capable of controlling the width of the pole to pole transition region for matching the stator geometry and thereby nearly eliminating cogging torque and reducing ripple torque.

Abstract: A drive circuit of an electromagnetic contactor including a series circuit of a surge absorber and a diode connected in parallel with the coil of the contactor, and a transistor connected in parallel with the surge absorber. There are two operation modes. In a first operation mode, the contactor is opened immediately after the contactor has been closed by a starting pulse. In a second operation mode, the contactor is opened after the contactor has been closed by a starting pulse and held by holding pulses following the starting pulse. In the first operation mode, the transistor is kept in an on state for a delay time after starting the contactor. This prevents the current due to counter electromagnetic force of the coil from flowing through the surge absorber before the current is reduced below the allowable level of the surge absorber by the transistor. This makes it possible to protect the surge absorber from being overheated.

Abstract: An electrical contactor has first and second contacts movably mounted to engage for achieving continuity in an electrical circuit, via an electromagnet and armature defining a magnetic circuit with an air gap that closes in a first position of the contactor and opens in a second position of the contactor. A controller switches an alternating current voltage to the coil of the electromagnet during a timed portion of each AC half cycle, and senses the current level in the coil in a feedback loop. The controller adjusts the voltage-on time to achieve a predetermined average current as needed for accelerating the armature or coasting during a closing operation, for holding the armature in place when closed, etc. In order to sense whether the contactor is presently open or closed, the controller monitors and stores the phase angle between the previous voltage zero crossing and the time of voltage turn-on.

Abstract: A control circuit for supplying a load with current having a high-amplitude ortion with a rapid leading edge, and a lower-amplitude portion. The circuit is input-connected to a low-voltage supply source, and comprises a number of actuator circuits parallel-connected between the input terminals and each including a capacitor and a load. Each actuator circuit also comprises a first controlled switch between the respective load and a reference line, for enabling energy supply and storage by the respective load. A second controlled switch is provided between the capacitor line and the load line, for rapidly discharging the capacitors into the load selected by the first switch and recirculating the load current, or for charging the capacitors with the recirculated load current.

Abstract: An active impulse magnetometer includes a magnetic field transmitter which generates a low frequency magnetic impulse waveform. A separate magnetometer receiver responds to the transmitted waveform, and produces a receive waveform which is transformed by a Fast Fourier Transform device into the frequency domain. The transformed signal is processed to indicate the presence of any detected objects.

Abstract: Rotation slip between the rotor and the armature of an electromagnetic clutch results in the exciting current I in the electromagnetic coil decreasing locally abruptly to form a unique waveform. The locally abruptly rising variations in the current is taken out as a locally abruptly variation (an alternating current component) in an inverted and amplified voltage, and the alternating current component is applied to a comparing circuit (400). The instantaneous value of the alternating current component is compared with a threshold which rises as the rotational speed of the rotor becomes higher, and while the instantaneous value exceeds the threshold, a comparison output is outputted. The comparison output is applied to a continuous waveform confirming circuit (500), and if the predetermined number of comparison outputs are detected with a predetermined time after a first comparison output has been generated, it is determined that a rotation slip has occurred.

Abstract: A deactivator for deactivating electronic article surveillance tags includes a deactivating coil, drive circuitry controllable for supplying driving signals to the deactivating coil, a reference signal generator for generating a reference signal having preselected characteristics varying with time, a comparator for comparing characteristics of the driving signals with the reference signal characteristics, and a control unit for controlling the drive circuitry in accordance with signal comparisons effected by the comparator.

Abstract: In a non-stage transmission control system, the output current instruction signal of a microcomputer is provided as a pulse-width-modulated signal, with a result that the number of signal lines from the microcomputer is reduced. Furthermore, the current feedback signal of a solenoid is applied to the microcomputer, for detection of abnormal conditions, and a quick break resistor is connected in series to a feedback diode to increase the current reduction rate of the solenoid.

Abstract: A current flowing to a fuel injector is completely cut off when an injection pulse signal is OFF at a timing to stop conduction of the fuel injector to reliability close the fuel injector, and when an injection pulse signal is OFF at a timing to stop conduction of an injector, an output transistor of a comparator is on to forcibly set a base potential of a switching transistor to a low level so as to completely cut off the switching transistor. At this time, a control signal output of an AND gate becomes a logic "0", but an actual signal voltage does not become completely "0", but even when a comparator is erroneously operated, the switching transistor is completely cut off by the comparator, and hence no current flows to the injector, and a small current continuously does not flow to the injector to prevent a valve closing force from being weakened.

Abstract: A circuit for increasing the reverse breakdown voltage of a bipolar transistor that provides drive current to an inductor has a voltage control transistor connected between the collector and base of the bipolar transistor, having a control element connected to one end of the inductor. The circuit can be fabricated as a portion of an integrated circuit formed on a single semiconductor substrate. Also disclosed is a method for increasing the emitter-collector breakdown voltage of a bipolar transistor in which the base and collector of the bipolar transistor are shorted when the emitter-collector voltage exceeds the breakdown voltage by turning on a transistor connected between the base and collector of the bipolar transistor.

Abstract: An electromagnetic switch device which features a mobile assembly having contacts cooperating with fixed contacts and displaced by a solenoid. The switch also features an analog sensor for measuring the position of the mobile assembly and electronics for processing the output signal of the position sensor to control the coil current.

Abstract: The system for timing the opening and closing of a high power switching arrangement breaker used in an electrical transmission system measures the temperature of the breaker and the phase of the power signal being switched. A control circuit provides a control signal for opening and closing the breaker in response to an initiating signal, the control signal being timed as a function of the temperature and the phase angle to make sure that contact is either made or broken at an appropriate time to reduce arcing. By taking into consideration temperature and its effects on the response of the breaker, arcing is significantly reduced.

Abstract: An electronic switching arrangement for controlling a coil includes a capacitor for energizing the coil by momentarily passing a current therethrough so as to generate a required attractive force for movement of the armature. After movement of the armature, only a lower holding current is supplied. Arranged parallel to the coil is a voltage divider which cooperates with a transistor to detect and evaluate an unintentional movement of the armature.

Abstract: A switched receptacle includes a latching relay selectively providing power to an outlet receptacle. A drive circuit for the latching relay provides indirect feedback to a logic controller which follows or tracks each relay operation to ensure that the relay is in the commanded mode.

Abstract: A counter electromotive force due to electromagnetic induction is generated on interruption of a current if an actuator 10 is in a normal state. An output signal generated by the counter electromotive force and a pulse signal which is generated from the fall of an input signal applied to the electronic switch are applied to an AND logical circuit 90 to determine whether or not the actuator is defective.

Abstract: An electromagnetic relay, which may be associated with further relays, has a supply circuit which includes means for generating a holding voltage for holding the relay contacts closed. This voltage generating means is activated and de-activated by receipt of an appropriate command signal for respectively closing and opening the relay contacts. The supply circuit includes a chopping circuit for chopping the highest unidirectional voltage available on the circuit, according to a cyclic ratio which is predetermined so as to provide a holding condition for the relay contacts at an intermediate voltage lower than the said highest available voltage, and with a low current. It also includes a circuit for generating a controlled closing voltage during the transition from the open to the closed position of the relay contacts. The invention is applicable especially to batteries of relays for use in motor vehicles.

Abstract: An electrical supply and switching circuit for the electrical fuel injectors of a fuel injection engine wherein a separate voltage supply circuit is provided for both the control circuit and driver circuit to minimize the effects of noise.

Abstract: In a clocked power end stage for an inductive load with a free-wheeling circuit, the speed of variation of the voltage at a connecting point between a load and a switch device as well as the speed of variation of the load current flowing through the switch device is adjustable, and in fact independently of the speed of variation of the voltage. In this way, a voltage which is proportional to the load current and one which is proportional to the drain voltage are respectively differentiated, and the signals so received are superimposed on the control clock signal for the switch device. With these measures, the electromagnetic disturbances caused by the clocking can be reduced.

Abstract: The system includes a direct-current voltage supply, an electric motor for rotating a movable pinion, and an electromagnetic operating device including a solenoid and an associated movable core. The core moves the pinion towards an operating position in which it can be coupled for rotation with a rotary member of the internal combustion engine. The connection between the electromagnetic operating device and the voltage supply is controlled by an electronic unit which measures the current flowing in the solenoid by means of a portion of the wire forming the solenoid, which portion is bent and preferably twisted, and acts as a resistive shunt.

Abstract: In a system for triggering an inductive consumer, particularly a consumer for controlling an internal combustion engine, the consumer is coupled via a circuit element to a voltage source. A control means triggers the circuit element in the switching mode for a preselected ON duration. Furthermore, means are provided for measuring the current flowing through the inductive consumer. To measure an actual current value, a first current value is measured shortly after the closing operation, and a second current value is measured immediately before the opening operation.

Abstract: In the case of a method and a device for triggering an electromagnetic consumer (1), which is connected in series to a switching means (2), the voltage applied to the switching means (2) is fed to a voltage comparison means (12) and compared there to the voltage of a reference voltage source (13). Dependent upon this voltage comparison, an output signal is produced at the output terminal of the voltage comparison means (12), which serves to switch over a suppressor device (4).

Abstract: In a vehicle electromagnetic clutch control device, a PWM modulator is provided in a microcomputer. In the microcomputer, a PWM modulation signal is calculated according to travel control data and engine control data and is then outputted. The PWM modulation signal is buffered by a digital signal buffer, the output of which is passed through a PWM smoothing filter to remove high frequency components of the signal. The output of the PWM smoothing filter is input to an analog buffer amplifier to output a substantially DC current instruction signal to a PWM comparator.

Abstract: A solenoid driver applies an actuation current to a solenoid for a predetermined period and a lower holding current thereafter. A switching device pulses the applied current within upper and lower limits to maintain the actuation and holding current amplitudes, the pulses being integrated by solenoid inductance into a substantially steady-state current. A multiprocessing unit determines the amplitudes of solenoid current. A signal representative of desired current amplitudes is compared with a signal representative of measured solenoid current, and a signal representative of the difference therebetween is used to control the switching device. Voltage developed across a resistor in series with the solenoid is input to a differential amplifier having connected to its output a peak detector that mimics the decay rate of current in the solenoid, the signal representative of measured solenoid current being obtained from the peak detector.

Abstract: In order to reduce the switch-on surge in current in the operation of an inductive load provided with a magnetizable core at an alternating mains current, in particular in pulse group operation, a switch-off-reset impulse is applied to this load following switching-off of the inductive load from the alternating current mains. This impulse has a polarity phased opposite to the last pulse group halfwave. In this way the remanent induction of the transformer core is shifted in a defined manner to lower values so that a defined remanence state of the iron core can be assumed when starting the next pulse group. This permits peak-current-free switching-on under any load and pulse period conditions. The remanent induction of the transformer core can also be maintained in the sector occurring immediately following switching-off of the inductive load, thus at the end of a pulse group.

Abstract: An apparatus for suppression of individual ignition events in an ignition system includes a short-circuit switch, connected in parallel to the primary winding of the ignition coil. The short-circuit switch is controlled by a control switch. In order to avoid having to provide a separate power supply to furnish triggering energy to the control switch, this energy is derived from the energy stored in the ignition coil during a closing phase of the ignition switch. This requires fewer components than prior art circuits designed for the same purpose.

Abstract: A synchronizing current regulator whose clock frequency is able to be readjusted is provided in the case of a circuit configuration for the synchronized supply of an electromagnetic user with regulation which is acted upon by a control signal representing the difference between the instantaneous signal at the user and a predeterminable reference signal.

Abstract: An electromagnetic clutch assembly for use with a refrigerant compressor for an automotive air-conditioning system includes a first rotatable member, such as a rotor, having an axial end plate of magnetic material and a second rotatable member connected to an outer end of a drive shaft of the compressor. An armature plate of magnetic material is elastically connected to the second rotatable member. The armature plate faces the axial end plate of the rotor with an axial air gap therebetween. An electromagnetic device is disposed within the rotor and is operable to attract the armature plate into contact with the axial end surface of the rotor such that the rotation of the rotor can be transmitted to the drive shaft when the electromagnetic device is activated.

Abstract: A fuel pump control circuit includes an SCR for controlling, after turning on of an ignition switch, power supply from a power source to a fuel pump circuit for driving a fuel pump (this SCR being turned on by a gate current supplied from the power source through a first conduction path), a timer circuit for shunting the gate current, which flows into the first conduction path, to a second conduction path when a predetermined time elapses after turning on of the ignition switch, and a current limiting resistor inserted in the first conduction path.

Abstract: Disclosed is a circuit device enabling an electromagnetic switch to be used with an A.C. power source. And the coil is thereof provided with a more stable electromagnetic field. The circuit device includes a releasing voltage detecting circuit, an engaging voltage detecting circuit, an nonstandard AND gate circuit connected to the detecting circuits, and a coil-holding circuit connected so that when there is an engaging voltage in the circuit device, the electromagnetic switch is energized and the coil is kept in a holding state. When there is a releasing voltage, the switch is de-energized.

Abstract: Power dissipation across the coils in a relay control system is controlled by regulating the voltage across all the coils with a regulator that senses the voltage and varies the conduction time of the switch carrying the total coil current. The regulator includes timing and logic elements that sense if the switch is operating correctly. Another switch is operated by the logic elements to shunt the first switch when the first switch is not operating correctly. This ensures that normal coil function is available in the event of a first switch failure.

Abstract: A solenoid driving circuit for an automatic transmission in which a potential difference compensating device, such as a Darlington-connected transistor circuit, switching transistor, and/or diode, is connected between a resistance element and a power ground, and a controlling device monitors voltage values at opposite sides of the resistor element so as to detect a current value flowing across a solenoid. The controlling device determines whether the detected value of the current flowing across the solenoid is abnormal, and the controlling device shuts off the current of a solenoid driving device when it is abnormal. The potential difference compensating device is provided with a switching device, and the controlling device turns off the switching device when the monitoring current value is abnormal.

Abstract: A low voltage switchgear with a single or multipole contact arrangement (1) with a corresponding number of fixed contacts (2) and movable contacts (3), a magnet armature (4) that moves the movable contacts (3), at least one magnet coil (5) that is energized by direct current and a setpoint switch release (9).

Abstract: A process for controlling and measuring the movement of an armature of an electromagnetic switching member with an excitation coil is proposed, which has the following steps: a current (i) or a voltage (u1) is applied to the excitation winding (3) in order to move the armature into a first actuatable position; before the start of the movement of the armature, the current or the voltage is raised above a value at which the armature remains in the actuated position, and before termination of the movement of the armature the current or the voltage is reduced to a defined value, which suffices to hold the armature in the actuated position; finally, the temporal variations in the current or the voltage are measured after setting of the defined value, for the purpose of recognizing the termination of the armature movement.

Abstract: A trigger circuit for an electromagnetic device, in particular a solenoid valve of an injection system for an internal-combustion engine, has a control element for causing excitation of the electromagnetic device to be lowered at least once and then raised after the electromagnetic device is activated. The control element has a delay circuit which slows down the rate at which excitation of the electromagnetic device changes during the lowering and/or raising action.

Abstract: A circuit for reversing a magnetic field in which a bifilar coil is provided with a series of two oppositely-wound windings that are connected together at one end to form a junction. A source of current is connected in series with an inductive resistor, and this series circuit is connected at one end to the junction. At the other end of this series circuit, there is a voltage supply source. Each of the two oppositely-wound windings has its other end connected to a variable switch. The two variable switches have control inputs that are connected to two outputs from a control unit which applies a reference potential to each winding through the variable switch, so that all current from the source of current flows through each winding upon closure of the respective variable switch.

Abstract: Load driver circuit (10) has first and second comparators (Cphd 1, C.sub.2) which receive a load current signal (V.sub.s) indicative of current flowing through a load (11). The comparators provide, as output signals, set on and set off signals (at 21, 23) in response to comparing the load current signal (V.sub.s) with first and second thresholds (T.sub.1, T.sub.2). Driver circuitry (27, 43, 12) receives the set on and set off signals and provides a current control signal (at 18) for controlling load current. Preferably, disabling circuitry (30-34) disables the comparators (C.sub.1, C.sub.2) after and in response to the comparators providing their respective output signals (at 21, 23). Also, preferably enabling circuitry (40-42) enables the comparators (C.sub.1, C.sub.2) in response to comparing a sensed voltage (at 17), indicative of voltage at an output terminal of a switching device (12) that controls load current, with respect to a predetermined voltage (2.5 volts).